SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c38361d4e10bd3670425ebabe7a3d8e3747badb9910b0ec9d671ac1a3f1f5ae6' 
  AND token = 'uEYpj9U86o/TsuOZ1Sj/C9XnebCcLOZ66UIuGrQ5v5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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