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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d514dc9e974e7e46b8f0a575f5dcc9db9e25e82ca7db26e137dc9de46fc2ec2' 
  AND token = 'QflyZN/6aczNZ9isY6Ir/wmsTuz4LeqvhTLr+TE44n0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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