SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ffe6952ae300585d3aa6b99ad59093f7d5449c63f9c24bfc4bbe88c0d64cf81' 
  AND token = '2QU8lg41BstY8Qmr6Ak9p0pi+K4PlTaP2k0G4wkbuWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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