SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84431763acbeff40a2e218a6e3163cb363f0b9143bec20097f7ceca319f6bebf' 
  AND token = '1DIf22f28dtLqO7LIS7FlFELYZK3D1scPBjyWATzTCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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