SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc0662c7396b2d0f694c44bc8291f8cd012d891e59a5e65bfeee89ab8501b6d1' 
  AND token = 'WHVU/q7vKO0SWQUXvlgJSkT5PwsFBTvvN1uiLNds83U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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