SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0a09fcd0f93eb6c17aae43e5737b3d140400a2a744f838028f41b238b48596d' 
  AND token = '2UBASUtGw8GrQ2+gHTfxDjkOtpnxDkoErDVjlc7Qwr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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