SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '816e833283e369d000328a64d359d234937194655bc7f1ebf8ccd99a2bc909d9' 
  AND token = 'pXzQJjrXG3t34QDFviKjq0q1ImwJ6iJefV8DlUEG2bs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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