SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '342ae118d461bf31a838a51734be66558c0d631960ecd8d2d7fb8e6578f6ba08' 
  AND token = 'irwJWS3YbwFDpGhuBTtGicVLCeg5OAozNWChNrRiJiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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