SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8750067734ff24388da0f32eb81bb2855e959a37eef5ef4602cf2e12c6b2b280' 
  AND token = 'Cke5Fnx4V81oQfi7lETU+cVdnHknfL4qfhf7Akl0tmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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