SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c11f090010ab57d2765059c479dc3d102dfba8fa58c1774c5fdca3ce36810ed6' 
  AND token = 'tW99jl6wBZW325vQKbw3ekhl+qDkfgHR+dXImRpzwG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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