SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5cb03f9971e92d38970985a638956a2eafcd517e0aec36b17e906e81fc0b936' 
  AND token = 'h/bhby9KkI1eeuyYtZ1wbr1q2KKDdUQIulnWq33cTSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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