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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e551ef9a0ea0e80cc99e0d961b95e1b4b50b085bcdb4454a6b5d77c68f42797' 
  AND token = 'YIUL9LAdF8NmtltOqr0RG7xQiCJzB3Q78e00F+VAK6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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