SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16b1d3c306b2cad4d179c89b3f25887d26d0a6a631d621f6c9247684fcff6098' 
  AND token = 'ohSXsfOQLXZdGAfGx0wXVzKKKBvJdtD6vbbDU5d/muk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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