SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbb75ddba4b37ebe6e73629b1d8ed6610b977fc031247856b2a94ae08ecf0c5a' 
  AND token = 'w+2xK2xTxeHDOZuCOLAK7zAHTvPxVpI4+EO6VczvEHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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