SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db6a50232bf77c7cf2b4dcade6b26b67ad84a1846f41e5eb90219ad5f1bb9941' 
  AND token = 'YnYA3aIQIs83vLHipPQ+juPv9UJ7U10Cg8p0zpxp/JU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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