SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b969bd6d5ef9f08b80628d7184fcf8bd925f1d44b5e52f0537120ca6461c61f7' 
  AND token = 'KbIThGUHSvSW7QU2ZXnGCUGJ2DUdKYksvowBzUYSftI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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