SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2b01d76ae0ebc56ee52c62b9145e0376bde6b9fda8f9cd6836f434ffa5f8471' 
  AND token = 'IP+Y8zn1rGUzGUarGNFb40gNLPzvO5ZvlMTv+8bWWEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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