SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30742c6ca4c8da4003482d1ef716112e3941f038664d463ee4ff527c442f1021' 
  AND token = 'buInMd29OFNJO4LXN4S6ucibnoikv/w1m+RgsgBQJwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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