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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'eb1dcab3c991ca2920fb2bcc5b4393ea88346ec68dd3b95e53918fada8e6553d' 
  AND token = 'GpTSQ8RCCcCH36IkuoQUoyLyYnlEXksFlZ5bjkoC+9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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