SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82e80b25e868ba544b477cca8b3843a7c4ab6b99f3a630df5f1afcf99cc52e31' 
  AND token = 'hdl5xj/MbCgGT7IBFwzfvY2MdCP4ZcbVnZ4ctm0Y1Qk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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