SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e75f66a6041441192350b17e22eb5cba2472eb660ecd97522a9828f22eef7744' 
  AND token = 'PKdvp6YZAMpHka56mSAqKUUm7NpPOMkmqnQ+yTGsSWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00094

JSON explain

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