SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96f743529fd89db97b7dfb153c25a4f06fccaacdc8fde75ebdcec70a1404f0e0' 
  AND token = 'r3RUW86W9kmjzz8QSnPGnitae9YBBNY+Wy2IQWSFws8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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