SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b8d2d579fdc0b3196fd1535f926d814ff6a83f033925ff60b1b0ae4bffad9b1' 
  AND token = 'sCFvHDpDM/LEooewpqHjcuvtuMQ8RBXAzhVPDW4EBi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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