SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b84fa26de249b02fff7488cd33c888e260be0ad9a512f5a3842ce887baf08bd1' 
  AND token = 'uf/3DFnLmdFBuhdGuUb9myYD+X372EMRaWZD8hBoTqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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