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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'df4a54fc65326e3bd89cb7ceee6cbcb39978512a09739a69e928f57827d7cbe2' 
  AND token = 'Q7tuFELAGYiE2uxMTaOGRN5KLK6GDE1zvmfpAWsCrOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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