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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b811c87281ef9ba1eca885910d4d752c1f1d2b2bb075b2f83ce3f04f6b2b565d' 
  AND token = 'qW4hF2i+RCHiGCgEp0OLEUSg6WFTOG5g8x8ZkqAKVpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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