SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5f93a00203dcabde6d07d69848b9b4e666c80b71573d53bae8204451c64f965' 
  AND token = 'zLW7aiBnmfJGHru1U+ChneL7uu2AvqT1/hue3YEVwVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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