SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a11a1f2c8009be27af8453ea9bbf382ad4ea7044d941a569ab73cf5184f945b' 
  AND token = '+MxEj/VJ2ycH9q3gZrhIlX1LLuBFLd9GXytNoBUAM6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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