SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fd9a301a7a0dd22c5421ea8f60972e743f4c565c7e63b3743ac0af85f6df3e0' 
  AND token = 'ps8hl+BgrD5sfmvSGjvJBjdzzPdiLZoYPOf7L+Ln7Is=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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