SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36af617b33025808b216521cdba699624fe281c4890b243c94a7e861893c9ecd' 
  AND token = 'KnKa5C+uNHH2OWKIVgKPjqHzwvKm0vpqZrNZ4TKJ8os=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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