SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5da04dae7a51b39881074518f6512f3bd906c86bc34dc66bc32ace978e19fc1' 
  AND token = 's/3B8RA6rLkOASaxBGQQeoijMagAvjWtknTOZLnVMEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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