SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20c133e2033f8c9afbc50adf6d6a50bb58d470a934502e0532520bdd3e7a2878' 
  AND token = 'qsyZ/4VDgsMLzl8CrdfLeXNFYKRU2gpxhMMk2mgg5UM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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