SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93a548f70df5315420d2bed92787e83f5247203fbd6f21d673751dd47245e30d' 
  AND token = 'ML1WygmIemQTUjpYqXghXiLtpoNj6pHnAn4i7NjPsws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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