SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3617cf1a478874f796875300fbbd48376c73d1289b69d3a0aba754ade90752c' 
  AND token = 'gnNFOAbbci1cQzniFe04FyZBOR0wHsvPVaWUJ/0Wmek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}