SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a732bd1244ae82e1143ed1fabbf63663e020f1858ef5c235fd39cdee883d4ac0' 
  AND token = 'Mx/JVBT9OH1ZvmgXa5aPJdTe0rBbqH3GMbFqOFeGsaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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