SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e13aca8a1f2b96c64f83ec38a083899a51897c975dfd3f769f910e06a865369a' 
  AND token = 'zlfrYOzsPolrlAeq3fiJvtwTqWFPFMs423akUYumZo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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