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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c60bb37ccf9bad049d8b98c88a9f3969cee7e50d2fa3af6017c02bd932f17ec' 
  AND token = '6DLL+ub3ydQVLxvKUQmqbpAraXYN2rT7MnV8gys2Oxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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