SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d997ca84872b4218902208968bff36f5840e7b2620d6409f066d2f3a09bad2c' 
  AND token = '47YWqzb2uCNVLVYJTNS1/Oy4YY7ijw/aqAA2BwpPGZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}