SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c08afba486d9cda7be819eb98c6be105fa141bc1bbe63276af626bdbdccc0f9' 
  AND token = '+FfStHufknZrKF6Zx3Br94QXcK7FQBj2sPvxxwV5YKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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