SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '341984160713df5e0f90b09c9b269da436f065b77f47b4affbf55c3aed83f13f' 
  AND token = 'x9K8Xnlu9q8WQXKRVsPv4bdEYKVB7IO+1LXsga6a/no=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}