SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8469a579d8598189faf75a283cb537631717ec894da046379117fd7b7f53ce2' 
  AND token = 'JL0CXhvZdxkBmiSZ/3iajUpkYPWSbbC3CQF5BdxMRlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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