SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b98e9201edad82829605bdbd80c2ecc198b4d0fa098d377c0f55ce6477a73266' 
  AND token = 'cgDA/x+yvR4VYxYWOoNAZKgHlfgOvvbwwpJ2TWFjyl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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