SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e1b11c2ca48240d85d13b252e1640fdb91031969a877606ff8de24664e574dc' 
  AND token = '09Kyd9XSqJ0iUH+TMvxnSPsIBlFuQ5oZc2oqGwZrHJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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