SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35928f46ea9493ddf02354cad5f727256db7cd82343e92edb0e639e2de8cb0c1' 
  AND token = 'jrRLemy86plVlTLW3JGDomlyeVXe4nD7+CIPqwOgCKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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