SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4ab7ea249bb526dabab19c463156cd207b826c28714f29732ddfdac80bda461' 
  AND token = 'L31PbA+brMJWTEIj+K0dbbSNav8bl32W/24fVvn1i94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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