SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e0a3f16f788f42da9260941307eb9205b0023bb7810d4fe7b940ed246b321c4' 
  AND token = 'HEgKrHyFIjaNluqD1wCoQ64u0r0ttQPm5km+QwQNipE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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