SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '838d4f51d6ba2965c101b42d3099413046f6d5a27797a1abc10a583bdfed6f81' 
  AND token = 'W4CEwoqQu8PeoFBVBaMpkl/5GLIuRHvXFrETQH/nROw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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