SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '743ac7f10c95c027da30449744299a31458cb42918398b183cbc76aa2f89bd38' 
  AND token = 'oJrj/uUUtu6W3QKU2HAphmZZfdbbo6itPTbbgXADflQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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