SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a6a445d58a05af264265be35ddbe72f0cb4291eee9a6ec1eba3f4d3c5ff4e23' 
  AND token = 'FZFc7CCf+EQJOyAF+ZlvCvUonTFC68VhQWcTfD/LDek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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