SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3a70d87975919652d31b0e631298f4e381930c8b3100aa6edd27b2ff254ccd9' 
  AND token = 'zcgMJ1O6iRAXmkhPvyI3fcBqGyKKZ/aGFdEB/mE6Dkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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