SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1342285e61ffe3e7f8186a1d9b2c44c98b5111726f76adad257b8e76c27d715' 
  AND token = 'pq6B1Fee3vMui/QLVqgSm4OVzMb2cAIU+YyjcfQG95M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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