SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45461e1d4cebea09ca453e582b45d1b6341f2d5814058dc2c3a81e2a8f499a7b' 
  AND token = '4c+CyFbsYPyjl0hQxfnFxHy3oPXi46kLJXP4lplJajg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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