SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68cb980abb64a4e97b5535f5e3bb1491a434ab478badb28b70be84f8772f10bf' 
  AND token = '982oRg9WPs7AW6YosPVKOU9P6o4Fyw8/a0mSVS04yAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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