SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cf33f7dd6fab2cebcff882d8136f820969fd03d21a9c1531ae8af74561312a9' 
  AND token = 'x/Qjk9naPYKeplPR2/hunoV+QUaEKuiz0f+LwqRhm4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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