SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d54136ce42084ea45292e693118b0ecaf11ba2c12d8f2f4ac024c2d758fe6a2' 
  AND token = 'Khr56b4sMAzTMV1ts1N12EXb5n47wekgqoYH6ODr5dI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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