SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc5d2dee5b3bf01c23f322f19340b3fb8746322eb745ca63af59a75cd5e90e49' 
  AND token = 'hQVCK9v9wCbjX/hecHhbWc+qX68zGvED2AwL4QKX4JY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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