SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89c7495fe212fbebd65afdd37a3b74bc4351e58a9ab5e57531a832b15892e7a5' 
  AND token = 'O4dIpbIjWSDQfJskQbR8Vrxks2/gfnYRVPPnNIqWTLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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