SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8f73356fbc4e8e436093d569610e718769929055efaed60a5b22261c55da37c' 
  AND token = '7yUHNf7fhV8S/loLmFpcJcZPYm083fXX4yoUTKC3t1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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