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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c6837a6e5c97b208eb30a1ff6dc6f999007b88f4aadc8abd0474dadb597bd4d8' 
  AND token = 'TUoiUrfn/zeq6gbjFFP1QMRm9EdCzBGg2P4pbeuEgaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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