SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62705cc6b44997ab10bb70b213c957f4a99d273273717f579a17fec4434d2c0c' 
  AND token = 'lcc2XnTvYwpMwXjpI8fAQ+qzVPBcBCTluUJkLAvgH6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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