SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afac43b4a8dab7fc467d77d04bf31c4a7ad6906ca8746b69953e9854836edf20' 
  AND token = 'zvZJ2YsimRCcFrWugLj859S9YufamS+ddWYJ0EOgVpc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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