SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2ebc497c69480d351cfa0eb6d9750a1faa02c389208cbd78f3c490c976cfb69' 
  AND token = 'JG0x/8Uw4idqdxds+pc/BMuJOL/hSniVSqLM1zpEMZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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