SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9907fd09480759ae58bce3cfa27c34fe4d22a05a14a38c2d278be8454e65977' 
  AND token = 'kJkHlosbeLzqJwtFDHcKYwGSS87ZSV4qCZNZjQINFbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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