SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8436e7edbb77a22dd0dd95fa1de1a1d7bd2db264b69f1ec6226b14da124cb10a' 
  AND token = 'DKrC7ihSkSdP0OQTLh/Eeyd24J7HhnC1KSvwI3bYfaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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