SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4c2d415ff55c924d23786326129b0e31b9fd4d066760678b32032610c5f433e' 
  AND token = 'X4XAfNDZnLonPioecM8jqTP65r+NsCk51Nu1RQYzjqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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