SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6c401e4134c6c1e84854f00e2f752ef34aba96451744e75ff4663c6abce8a42' 
  AND token = '4SKWR9BPERbOW5wrsVwq6dQOGlhH13Zlhn4grpWXVtE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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