SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f302fb19b7d7cd32a5f58fb26219876b388cb9e4ade56b922f49a4b72cba3d44' 
  AND token = 'UjafzvlDy4ZPB4zBIlfkWs5aJI0WvRwvCnLoaZxxsjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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